Experimental and numerical investigations on ultimate strength of ship plates under longitudinal cyclic loads

Research on the ultimate strength behavior of ship plates under longitudinal cyclic loads is one of the basic works when studying on the hull girder's ultimate strength under cyclic bending loads, which is meaningful to guarantee the longitudinal strength safety of ship hulls. In this paper, a series of tests to the seven square column models is carried out to simulate the ultimate strengths of ship plates under the loads of cyclic axial compression. In addition, it conducts numerical analysis to these models by the nonlinear finite element analysis. The studied results indicate that ship plate's compressive ultimate strength based on one-time collapse is the maximum of ship plates' ultimate strength under the load of cyclic axial compression; therefore, the assessment criteria of hull girder's ultimate strength based on one-time collapse may overestimate the load bearing capability of actual ship hull structures. The conclusions in this paper are significant to understand the hull girder's ultimate strength under the cyclic loads and impel further study on this subject.